In congestive heart failure (CHF) compensatory mechanisms are activated that increase systemic vascular resistance (SVR) and redistribute cardiac output. Recent investigators using angiotensin (R-A) system may participate in these pathophysiological changes. The overall objective of this investigation is to extend these observations in normal man and in patients with CHF using CEI. In addition to central hemodynamic measurements the regional circulation of the kidney, liver and heart will be studied. The local and reflective changes that occur in limb vascular tone after CEI will also be examined. Central and peripheral circulatory responses to exercise are inadequate in patients with CHF. The contribution of the R-A system in these circulatory abnormalities has not been clarified. CEI will be utilized to study the influence of the R-A system during dynamic exercise on forearm blood flow. CEI will also be used to study the effect of angiotensin blockade on central hemodynamics as measured by Swan-Ganz catheterization and gated blood pool scan. In order to compare the exercise response of CEI to the response of a nonspecific vasodilator, a double blind exercise trial using Captopril and Hydralazine will be made. Changes in plasma renin activity, aldosterone and norepinephrine concentrations and bradykinin activity will be correlated with the central and regional hemodynamic observations. This research may better define the role of the R-A system in the regulation of central and peripheral circulation in normal man and in patients with CHF at rest and during exercise and may provide an innovative approach to therapy in refractory CHF.